Portable integrated circuit cards, also referred to as flash memory cards, are popularly used with portable consumer devices such as digital cameras, celluar phones and audio players for the storage of data, such as images, music video and other information. Such cards usually contain a reprogrammable non-volatile semiconductor memory cell array along with a controller that controls operation of the memory cell array and interfaces with a host device to which the card is electrically connected. Such flash memory cards have been commercially implemented according to a number of well-known standards, such as Compact Flash (CF) cards, MultiMediaCards (MMC), Secure Digital (SD) cards and Memory Sticks.
The advantage of these flash memory cards is that they store information without requiring a power source and are solid state devices with no moving parts. They are also compact in size. FIGS. 1(a) and 1(b) show front and back views respectively of an exemplary memory card in the form of a secure digital (“SD”) memory card.
A conventional method of manufacturing memory cards is to first bond integrated circuit chips or dice onto substrates in an array form, then wire-bonding the dice to the substrates to electrically connect them. Thereafter, wire-bonded dice are molded to protect them from the environment. The molding is usually performed using block molding, wherein multiple dice are molded within a single stick or block, or in several islands, each molded portion comprising multiple dice.
Since multiple dice are molded together, each individual die comprised in a molded portion needs to be separated from the others by dicing or cutting through the molded material. Memory cards typically incorporate special shapes and features, such as chamfers to aid insertion to a host device during use. Special cutting techniques must be used to cut these shapes and features as the components are fragile and small in size. For example, abrasive water jet cutting is conventionally used to cut out irregular profiles from the molded block, then a saw is used to cut the remaining straight edges to singulate individual memory cards.
As memory cards are getting smaller, it is getting more difficult to maintain singulation quality. The process is also relatively slow. Furthermore, dicing requires further processing to wash and dry the individual memory cards to remove debris. Only then can inspection and final testing be performed. These processes incur increased time and costs.
It would be desirable to employ a molding technique for memory card packages that allow the respective profile of each memory card device to be created during molding rather than after molding. After molding, it would be desirable to be able to sever individual memory cards from the molded array by simply punching each memory card out from the array without the need for conventional dicing and its attendant disadvantages.